Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, and so on. Typical wireless communication systems are multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and others. These systems are often deployed in conformity with specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), evolution data optimized (EV-DO), etc.
In cellular networks, macro scale base stations (or macro NodeBs (MNBs)) provide connectivity and coverage to a large number of users over a certain geographical area. A macro network deployment is carefully planned, designed, and implemented to offer good coverage over the geographical region. Even such careful planning, however, cannot fully accommodate channel characteristics such as fading, multipath, shadowing, etc., especially in indoor environments. Indoor users therefore often face coverage issues (e.g., call outages and quality degradation) resulting in poor user experience.
To extend cellular coverage indoors, such as for residential homes and office buildings, additional small coverage, typically low power base stations have recently begun to be deployed to supplement conventional macro networks, providing more robust wireless coverage for mobile devices. These small coverage base stations are commonly referred to as Home NodeBs or Home eNBs (collectively, H(e)NBs), femto nodes, femtocells, femtocell base stations, pico nodes, micro nodes, etc., deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and so on. Such small coverage base stations may be connected to the Internet and the mobile operator's network via a digital subscriber line (DSL) router or a cable modem, for example.
An unplanned deployment of large numbers of small coverage base stations, however, can be challenging in several respects. For example, in a macro network, each macro base station (or each sector or cell thereof) is assigned not only a global identifier (e.g., a global cell identifier (GCI), a sector identifier (SectorID), an access node identifier (ANID), or some other type of identifier), but also a local identifier (e.g., a physical cell identifier (PCI), a pilot pseudorandom number (PilotPN), or some other type of identifier). The local identifier can use fewer bits because of its limited geographical reach, and is therefore more amenable for use in modulating physical layer channels. In this way, a user device can efficiently search for waveforms, such as pilot signals, corresponding to different local identifiers to identify the cells in the user device's vicinity and demodulate their transmissions. For the same reasons, however, the number space allocated for local identifiers is relatively limited. Yet, it is desirable for a network operator to ensure that the same local identifier is not used by base stations that are relatively close to each other, in order to avoid identifier conflict (e.g., identifier collision and/or identifier confusion).
While this may be feasible in a traditional planned network, it may not be feasible in an unplanned or ad-hoc network such as one employing many small coverage base stations. In such networks, the network operator or a customer often deploys the small scale base station without knowing which local identifiers would cause identifier conflict in the network. Thus, there is a need for effective techniques for detecting identifier conflict in wireless networks, such that remedial action can be taken.